Extrusion head for plastic materials

ABSTRACT

An extrusion head for plastic materials. The extrusion head is characterized in that a distribution plate is interchangeable. The distribution plate includes at least one distribution network for the extruded materials, so as to determine the characteristics of at least one type of type produced by the extrusion operation through its conformation.

TECHNICAL FIELD

The present invention concerns an extrusion head for plastic materials.

In particular, this extrusion head can be used for the coextrusion oftwo materials having different chemical-physical and/or colorimetriccharacteristics.

BACKGROUND ART

It is known that very thin strips of plastic material, known as tapes,are used in the creation of artificial.

In order that artificial grass approximates to natural grass in acredible manner, from a visual standpoint, it is important that thetapes do not all have the same colour.

For example, each tape can have a first face with a first colour (e.g.dark green), and a second face with a second colour (e.g. light green).

As shall be seen, by means of the extrusion head, the subject of thepresent invention, it is possible to obtain tapes having the colouringof a first material, the colouring of a second material, or a first facecoloured according to a first material and a second face with the colourof a second material, by simply changing a distribution plate.

DISCLOSURE OF INVENTION

Thus, according to the present invention, an extrusion head is embodiedin accordance with the enclosed claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention shall now be described with reference to theenclosed drawings, which illustrate non-limitative examples ofembodiment, where:

FIG. 1 illustrates a section A-A of a first embodiment of an extrusionhead, the subject of the present invention,

FIG. 2 shows a view C-C of a detail of the extrusion head in FIG. 1,

FIG. 3 illustrates a section B-B of the extrusion head shown in FIGS. 1and 2,

FIG. 4 shows a view D-D of a detail of the extrusion head illustrated inFIGS. 1, 2 and 3,

FIG. 5 illustrates a view E-E of a detail of the extrusion headillustrated in FIGS. 1, 2, 3 and 4,

FIG. 6 shows a section F-F of a second embodiment of an extrusion head,the subject of the present invention,

FIG. 7 illustrates a view G-G of a detail of the extrusion head in FIG.6,

FIG. 8 shows a view H-H of a detail of the extrusion head illustrated inFIGS. 6 and 7,

FIG. 9 illustrates a view I-I of a detail of the extrusion headillustrated in FIGS. 6, 7 and 8,

FIG. 10 shows a section L-L of a third embodiment of an extrusion head,the subject of the present invention,

FIG. 11 illustrates a view M-M of a detail of the extrusion head in FIG.10,

FIG. 12 shows a view N-N of a detail of the extrusion head illustratedin FIGS. 10 and 11, and

FIG. 13 illustrates a view O-O of a detail of the extrusion headillustrated in FIGS. 10, 11 and 12.

BEST MODE FOR CARRYING OUT THE INVENTION

In FIGS. 1, 2, 3, 4 and 5, reference numeral 100 indicates, in itsentirety, a first embodiment of an extrusion head for plastic materials,the subject of the present invention.

The extrusion head 100 comprises, from the top downwards:

-   -   a spacer element 101    -   a first distribution plate 102,    -   a second distribution plate 103,    -   a third distribution plate 104,    -   a preform die 105, and    -   a die 106        packed one on top of the other and held together by clamping        means (e.g. clamping screws) that are not shown in the enclosed        figures so as not to compromise legibility.

Representations of the electrical resistances that serve to heat theextrusion head 100 to keep the plastic materials to be extruded in thefluid state have also been omitted from the enclosed drawings.

The various elements packed one on top of the other are substantiallysymmetrical with respect to a plane, which is traced on the drawingsheet as axis (X) (FIG. 2).

The spacer element 101 is provided with two inlet channels for twodifferent plastic materials. These different plastic materials can havedifferent chemical-physical characteristics and/or different colours.

Entering into greater detail, a duct 107 a having a respectivelongitudinal axis of symmetry (A) and a duct 108 a having a respectivelongitudinal axis of symmetry (B), have been created in thesubstantially parallelepipedal spacer element 101.

The ducts 107 a-108 a are the terminal portions of the feed channels(not shown) of two different plastic materials in the semi-liquid state.

As shall be better seen in the following, duct 107 a is able to convey afirst plastic product having, for example, a first colour, while asecond plastic product having, for example, a second colour, flowsthrough the second duct 108 a.

In series with duct 107 a there is a duct 107 b made in the firstdistribution plate 102, such that the set of the two ducts 107 a-107 bin series form a feed channel 107 (with axis (A)) for the first product.

Similarly, in series with duct 108 a there is a second duct 108 b, madein the first distribution plate 102, and a third duct 108 c obtained inthe third distribution plate 103. the set of ducts 108 a-108 b-108 c inseries form a feed channel 108 (with axis (B)) in which the secondproduct flows, which, as already mentioned, generally has differentchemical-physical and/or colorimetric characteristics from the firstproduct.

A first distribution network 109 for the first product is made in aninterface INTF1 between the first distribution plate 102 and the seconddistribution plate 103. This first distribution network 109 has aU-shape, with a branch 109 a transversal to axis (X) and two branches109 b-109 c parallel to the same axis (X).

Furthermore, between the second distribution plate 103 and the thirddistribution plate 104, there is an interface INTF2 in which there is asecond distribution network 110 for the first product including twobranches 110 a-110 b both parallel to axis (X).

Similarly to that seen above, a third distribution network 111, alwaysfor the first product, is allocated in an interface INTF3 between thethird distribution plate 104 and the preform die 105.

In turn, the third distribution network 111 includes two branches 111 a,111 b.

Branch 111 a (FIG. 4) comprises a duct 111 a* parallel to axis (X) and aplurality of ducts 111 a** perpendicular to the same axis (X). Each duct111 a** terminates in a respective extrusion outlet 112 (FIG. 5) fromwhich the first finished extruded product emerges. The extrusion outlet112 has the shape of a slit parallel to axis (A) and affects the preformdie 105 and the die 106.

Similarly, branch 111 b comprises a duct 111 b* parallel to axis (X) anda plurality of ducts 111 b** perpendicular to the same axis (X). Eachduct 111 b** terminates in a respective extrusion outlet 112 from whichthe finished extruded product emerges.

As shown, always in FIGS. 1, 2, 3, 4 and 5, the first distributionnetwork 109 for the first product is connected to the seconddistribution network 110 for the same product via a plurality ofvertical conduits 113, parallel to axis (A) (FIG. 1).

Furthermore, a plurality of conduits 114, these also vertical andparallel to axis (A), is provided between the second distributionnetwork 110 for the first product and the third distribution network111. Each conduit 114 is the continuation of the respective conduit 113.

The feed channel 108 for the second product terminates in a fourthdistribution network 115 situated in the interface INTF2 between thesecond distribution plate 103 and the third distribution plate 104.

The fourth distribution network 115 for the second product is U-shapedand is identical to the first distribution network 109. This fourthdistribution network 115 therefore has a branch 115 a transversal toaxis (X) and two branches 115 b-115 c parallel to the same axis (X).

Furthermore, branches 115 b and 115 c of the fourth distribution network115 for the second product are parallel to branches 110 a and 110 b ofthe second distribution network 110.

Moreover, a fifth distribution network 116, always for the secondproduct, is situated in the interface INTF3 between the thirddistribution plate 104 and the preform die 105.

In turn, the fifth distribution network 116 includes two branches 116 a,116 b.

Branch 116 a comprises a duct 116 a* parallel to axis (X) and aplurality of ducts 116 a** perpendicular to the same axis (X). Each duct116 a** terminates in a respective extrusion outlet 112 from which thesecond finished extruded product emerges.

Similarly, branch 116 b comprises a duct 116 b* parallel to axis (X) anda plurality of ducts 116 b** perpendicular to the same axis (X). Eachduct 116 b** terminates in a respective extrusion outlet 112 from whichthe finished extruded product emerges.

In other words, each duct 111 a** (in which the first product isextruded) faces a respective duct 116 a** (in which the second productis extruded) and each duct 111 b** (in which the first product isextruded) finds itself facing a respective duct 116 b** (through whichthe second product is extruded).

In addition, each pair formed by ducts 111 a** and 116 a**, and,respectively, by ducts 111 b** and 116 b** flow into the same respectivecoextrusion outlet 112 for the two materials, so as to obtain, forexample, tape with different coloured faces.

A plurality of conduits 117, these also vertical and parallel to axis(B), is provided between the fourth distribution network 115 for thesecond product and the fifth distribution network 116.

It should be noted that the outlet 112 in the first embodiment shown inFIGS. 1, 2, 3, 4 and 5 is the same for the two products to be extruded.

In this way, as they are coextruded in the outlets 112, the two productsform tapes, each having two faces with different properties, such asdifferent colours for example.

The problem of simultaneously coextruding two plastic materials havingdifferent characteristics using the same outlets 112 is thus resolved ina simple and inspired manner.

In the second embodiment shown in FIGS. 6, 7, 8 and 9, a thirddistribution plate 204, different from the distribution plate 104previously described with reference to the first embodiment illustratedin FIGS. 1, 2, 3, 4 and 5, has been adopted in an extrusion head 200.

In FIGS. 6, 7, 8 and 9, the first figure of the reference numbers hasbeen changed to “2” because they substantially indicate the sameelements regarding the first embodiment shown in FIGS. 1, 2, 3, 4 and 5.

In fact, in this case, a third distribution network 211 (FIG. 8) for afirst product includes, in turn, two branches 211 a-211 b. Branch 211 acomprises a duct 211 a* parallel to axis (X) and a plurality of ducts211 a** perpendicular to the same axis (X) that are not equally spacedout between each other. Each duct 211 a** terminates in a respectiveextrusion outlet 212* or 212**.

Incidentally, it should be noted that the extrusion outlets in which thesecond product is also coextruded with the system seen in the firstembodiment are identified by reference number 212*, while 212**indicates the extrusion outlets in which only the first product isextruded.

Similarly, branch 211 b comprises a duct 211 b* parallel to axis (X) anda plurality of ducts 211 b** perpendicular to the same axis (X) that arenot equally spaced out between each other. Each duct 211 b** terminatesin a respective extrusion outlet 212* or 212** from which the finishedextruded product emerges.

Regarding the second plastic product, the fifth distribution network 216has two branches 216 a and 216 b. Branch 216 a comprises a duct 216 a*parallel to axis (X) and a plurality of ducts 216 a** perpendicular tothe same axis (X) that are not equally spaced out between each other.

Each duct 216 a** terminates in a respective coextrusion outlet 212*, orterminates in a respective outlet 212*** from which only the secondfinished extruded product emerges.

As can be noted from observation of FIG. 8, outlets 212** (for extrusionof just the first product) are inserted in between outlets 212*** (forextrusion of just the second product).

Similarly, branch 216 b comprises a duct 216 b* parallel to axis (X) anda plurality of ducts 216 b** perpendicular to the same axis (X). Eachduct 216 b** terminates in a respective coextrusion outlet 212* or212***, or terminates in a respective outlet 212*** from which only thesecond finished extruded product emerges.

Outlets 212** (for extrusion of just the first product) are inserted inbetween outlets 212*** (for extrusion of just the second product).

Incidentally, it should be noted that the extrusion outlets in whichboth products are simultaneously coextruded with the system seen in thefirst embodiment are identified by reference number 212*, while tapesmade with just the first product emerge from extrusion outlets 212** andoutlets 212*** are the extrusion outlets in which only the secondproduct is extruded.

Furthermore, the coextrusion outlets 212* of both products arepositioned all in a row, one behind the other, while the extrusionoutlets 212** for just the first product are inserted in between theextrusion outlets 212*** for just the second product.

Consequently, there is a first series of coextruded tapes having facesmade with two different products, a second series of tapes made onlywith the first product and a third series of tapes obtained by extrusionof just the second product.

In the third embodiment shown in FIGS. 10, 11, 12 and 13, a thirddistribution plate 304, different from the third distribution plate 104previously described with reference to the first embodiment illustratedin FIGS. 1, 2, 3, 4 and 5, has been adopted in an extrusion head 300.Furthermore, the third distribution plate 304 is also different from thethird distribution plate 204 utilized in the second embodiment ofpresent invention and described with reference to FIGS. 6, 7, 8 and 9.

In FIGS. 10, 11, 12 and 13, the first figure of the reference numbershas been changed to “3” because they substantially indicate the sameelements regarding the first embodiment shown in FIGS. 1, 2, 3, 4 and 5,and the second embodiment illustrated in FIGS. 6, 7, 8 and 9.

In the third embodiment (FIGS. 10, 11, 12 and 13), extrusion outlets312** alternating with extrusion outlets 312*** (FIGS. 12 and 13) areprovided in the manner seen for the second embodiment. As the solutionadopted in the third embodiment is substantially identical to part ofthat described in the second embodiment with regard to extrusion outlets212** and 212***, to not make the present description overlong, pleaserefer to the description concerning the second embodiment shown in FIGS.6, 7, 8 and 9.

It is also important to note that one of the most interestingcharacteristics of the extrusion head 100, 200 and 300, the subject ofthe present invention, consists in the fact that simply changing thethird distribution plate 104 (FIG. 1), 204 (FIG. 6) and 304 (FIG. 10)results in producing tapes with different characteristics.

The main advantage of the extrusion head, the subject of the presentinvention, consists in its extreme versatility, due to the fact that bysimply changing a distribution plate for the plastic materials in thesemi-liquid state, tapes are obtained that have differentcharacteristics and which can be used, for example, to create artificialgrass with a very pleasing visual effect, and in all those cases wheredual colouring of the same monofilament is required. Furthermore,considering that the monofilaments are wound onto reels, with the systemin question it is possible to produce reels with different colours orcombinations of threads with colour A and colour B in a single windingoperation, avoiding further production steps that without the aid of thehead in question, must instead be carried out. However, neither shouldthe high flexibility of the system be overlooked, which ensuresunlimited choice in the ratio of the number of threads with differentcolours and the winding method.

1. Extrusion head for plastic materials including: distribution means;and extrusion means, with said distribution means and said extrusionmeans being packed one on top of the other and held together by clampingmeans, wherein at least one distribution plate, belonging to saiddistribution means, is interchangeable, and in that said at least onedistribution plate includes at least one distribution network for thematerials to extrude, such that the characteristics of at least one tapeare determined by the conformation of said distribution network. 2.Extrusion head, as claimed in claim 1, wherein it includes: a spacerelement; a first distribution plate; a second distribution plate; athird distribution plate; a preform die; and a die, wherein the spacerelement, the first distribution plate, the second distribution plate,the third distribution plate and the perform die and the die are packedone on top of the other and held together by clamping means. 3.Extrusion head, as claimed in claim 1, wherein said at least onedistribution network for a first product comprises two branches, with afirst branch, in turn, including a first duct, parallel to alongitudinal axis of symmetry (X), and a first plurality of ductsperpendicular to the same axis (X), in which each duct terminates in arespective extrusion outlet, and with a second branch including a secondduct parallel to axis (X) and a second plurality of ducts perpendicularto the same axis (X), in which each duct terminates in a respectiveextrusion outlet.
 4. Extrusion head, as claimed in claim 3, wherein italso includes a second distribution network for a second productcomprising a further two branches, with a third branch, in turn,including a third duct, parallel to axis (X), and a third plurality ofducts perpendicular to the same axis (X), in which each duct terminatesin a respective extrusion outlet in which a respective duct of saiddistribution network also terminates, so as to achieve coextrusion ofthe first product and the second product in each of their respectiveextrusion outlets, and with a fourth branch including a fourth ductparallel to axis (X) and a fourth plurality of ducts perpendicular tothe same axis (X), in which each duct terminates in a respectiveextrusion outlet in which a respective duct of said distribution networkalso terminates, so as to achieve coextrusion of the first product andthe second product in the extrusion outlet itself.
 5. Extrusion head, asclaimed in claim 4, wherein the distribution network for the firstproduct is fed by means of a feed channel, by means of a furtherdistribution network and by means of conduits, and in that the seconddistribution network for the second product is fed by means of a secondfeed channel, by means of a second further distribution network and bymeans of second conduits.
 6. Extrusion head, as claimed in claim 1,wherein said at least one distribution network for a first productcomprises two branches, with a first branch, in turn, including a firstduct parallel to a longitudinal axis of symmetry (X), and a firstplurality of ducts perpendicular to the same axis (X) that are notequally spaced out between each other, in which each duct terminates ina respective extrusion outlet, and with a second branch including asecond duct parallel to axis (X) and a second plurality of ductsperpendicular to the same axis (X) that are not equally spaced outbetween each other, in which each duct terminates in a respectiveextrusion outlet.
 7. Extrusion head, as claimed in claim 6, wherein italso includes a second distribution network for a second productcomprising a further two branches, with a third branch, in turn,including a third duct parallel to axis (X), and a third plurality ofducts perpendicular to the same axis (X) that are not equally spaced outbetween each other, in which each duct terminates in a respectivecoextrusion outlet, or terminating in a respective outlet from whichonly the second finished extruded product emerges, and with a fourthbranch including a fourth duct parallel to axis (X) and a fourthplurality of ducts perpendicular to the same axis (X), in which eachduct terminates in a respective coextrusion outlet in which a respectiveduct of said distribution network also terminates, or terminates in arespective outlet from which only the second finished extruded productemerges.
 8. Extrusion head, as claimed in claim 7, wherein thedistribution network for the first product is fed by means of a feedchannel, by means of a further distribution network and by means ofconduits, and in that the second distribution network for the secondproduct is fed by means of a second feed channel, by means of a secondfurther distribution network and by means of a second set of conduits.9. Extrusion head, as claimed in claim 7, wherein extrusion outlets arecoextrusion outlets for both products, extrusion outlets are extrusionoutlets for just the first product, while extrusion outlets areextrusion outlets for just the second product.
 10. Extrusion head, asclaimed in claim 9, wherein the outlets for extrusion of just the firstproduct are inserted in between the outlets for extrusion of just thesecond product.
 11. Extrusion head, as claimed in claim 1, wherein saidat least one distribution network for a first product comprises twobranches, with a first branch, in turn, including a first duct parallelto a longitudinal axis of symmetry (X), and a first plurality of ductsperpendicular to the same axis (X), in which each duct terminates in arespective extrusion outlet, and with second branch (311 b) including asecond duct parallel to axis (X) and a second plurality of ductsperpendicular to the same axis (X), in which each duct terminates in arespective extrusion outlet from which only the first extruded productemerges.
 12. Extrusion head, as claimed in claim 11, wherein it alsoincludes a second distribution network for a second product comprising afurther two branches, with a third branch, in turn, including a thirdduct parallel to axis (X), and a third plurality of ducts perpendicularto the same axis (X), in which each duct terminates in a respectiveoutlet from which only the second finished extruded product emerges, andwith a fourth branch including a fourth duct parallel to axis (X) and aforth plurality of ducts perpendicular to the same axis (X), in whicheach duct terminates in a respective outlet from which only the secondfinished extruded product emerges.
 13. Extrusion head, as claimed inclaim 12, wherein the distribution network for the first product is fedby means of a feed channel, by means of a further distribution networkand by means of conduits, and in that the second distribution networkfor the second product is fed by means of second a feed channel (308),by means of a second further distribution network and by means of asecond set of conduits.
 14. Extrusion head, as claimed in claim 12,wherein the extrusion outlets of the first branch are the extrusionoutlets for just the first product, while the extrusion outlets of thesecond branch are the extrusion outlets for just the second product. 15.Extrusion head, as claimed in claim 14, wherein the outlets forextrusion of just the first product are inserted in between the outletsfor extrusion of just the second product.
 16. An apparatus for extrudingplastic materials comprising: at least one distribution plate defining afirst inlet channel to receive a first fluidic material and distributethe first fluidic material to a first distribution network and a secondinlet channel to receive a second fluidic material and to distribute thesecond fluidic material to a second distribution network; and at leastone die defining a plurality of extrusion outlets, with a first portionof each extrusion outlet in fluid communication with the firstdistribution network, and with a second portion of each extrusion outletin fluid communication with the second distribution network, with eachextrusion outlet shaped to extrude a tape with a first side formed ofthe first fluidic material and the second side formed of the secondfluidic material.
 17. The apparatus of claim 16, wherein the at leastone distribution plate includes: a first distribution plate coupled tothe spacer element; a second distribution plate coupled to the firstdistribution plate; and a third distribution plate coupled to the seconddistribution plate, wherein the first network is defined by the first,second and third plates and the second distribution network is definedby the second and third plates.
 18. The apparatus of claim 17, whereinthe at least one die includes: a preform die; and a die coupled to theperform die, wherein the perform die and the die together define eachextrusion outlet.
 19. the apparatus of claim 16, wherein the at leastone die defines a second plurality of extrusion outlets coupled only tothe first distribution network, the second plurality of extrusionoutlets to make a tape formed of only the first fluidic material. 20.the apparatus of claim 16, wherein the at least one die defines a thirdplurality of extrusion outlets coupled only to the second distributionnetwork, the third plurality of extrusion outlets to make a tape formedof only the second fluidic material.